Factors That Affect Logix Reaction-time Components

A number of factors can influence the Logix system reaction time components.
Network traffic and EMC create a lower limit for the values that you can successfully use for the timeout multiplier and network delay multiplier.
System Reaction Time Components
Reaction Time Component
Factors
Safety task reaction time
Safety function muting during qualification, loss of redundancy, or a lock for update impacts the safety task reaction time in high demand applications.
Input device delay
  • Input device reaction time
  • On-Off and Off-On delay settings for each input channel
Safety input connection reaction time limit
  • Input device settings:
    • Requested packet interval (RPI)
    • Timeout multiplier
    • Network delay multiplier
  • The amount of network communication traffic.
  • The EMC environment of the system
Safety task period and safety task watchdog
  • Safety task period setting
  • Safety task watchdog setting
  • The number and execution time of instructions in the safety task The instructions in your safety task create a lower limit for the values that you can successfully use for the safety task period and safety task watchdog.
Output connection reaction time limit
  • Safety task period setting
  • Output device settings:
    • Timeout multiplier
    • Network delay multiplier
  • The amount of network communication traffic
  • The EMC environment of the system
Output module delay
Output module reaction time
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